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Finding the Fourth Proportional to 643.91, 963.78 and 458.70

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Solution

The fourth proportional to 643.91, 963.78 and 458.70 is: 686.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.91 : 963.78 = 458.70 : x
  2. Step 2: Convert to fraction form
    643.91/963.78 = 458.70/x
  3. Step 3: Cross multiply
    643.91x = 963.78 × 458.70
  4. Step 4: Simplify right side
    643.91x = 442,085.89
  5. Step 5: Solve for x
    x = 442,085.89/643.91
  6. Step 6: Final answer
    x = 686.57

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.